Chemically Amplified Positive Resist Composition and Resist Pattern Forming Method

Abstract

The present invention provides a chemically amplified positive resist composition for a resist film that can form a pattern with extremely high resolution, small LER, excellent rectangularity, and suppressed influence of development loading, and a method for forming a resist pattern. A chemically amplified positive resist composition includes a base polymer, and the base polymer contains: a polymer containing an acid generating unit, a phenolic hydroxyl group-containing unit, a unit in which a phenolic hydroxyl group is protected by an acid-labile group, and a unit in which a carboxyl group is protected by an acid-labile group, or a polymer containing an acid generating unit, a phenolic hydroxyl group-containing unit, and a unit in which a phenolic hydroxyl group is protected by an acid-labile group, and a polymer containing an acid generating unit, a phenolic hydroxyl group-containing unit, and a unit in which a carboxyl group is protected by an acid-labile group; among all the repeating units of the polymers contained in the base polymer, the repeating units having an aromatic ring skeleton are 60 mol% or more.

Description

Technical Field

[0001] The present invention relates to a chemically amplified positive resist composition and a method for forming a resist pattern. Prior Art

[0002] In recent years, with the high integration of integrated circuits, the formation of finer patterns has been required. For the processing of patterns of 0.2 μm or less, a chemically amplified resist composition using an acid as a catalyst is mainly used. At this time, high-energy rays such as ultraviolet rays, far ultraviolet rays, extreme ultraviolet rays (EUV), and electron beams (EB) are used as the exposure source. In particular, EB lithography used as a superfine processing technology has become indispensable in the processing method of a blank photomask when manufacturing a photomask for semiconductor manufacturing.

[0003] Generally, in EB lithography, the drawing by EB is performed without using a mask. In the case of a positive type, EB of a fine area is sequentially irradiated to a portion other than the area to be retained of the resist film, and in the case of a negative type, EB of a fine area is sequentially irradiated to the area to be retained of the resist film. That is, scanning is performed over all the finely divided areas of the processing surface, so it takes more time than batch exposure using a photomask. In order not to reduce the production capacity, a highly sensitive resist film is required. In particular, in the processing of a blank photomask for an important use, a surface material such as a chromium compound film such as chromium oxide already formed on the photomask substrate may affect the pattern shape of the chemically amplified resist film. In order to maintain high resolution and the shape after etching, it is also an important performance to maintain the pattern profile of the resist film as a rectangle regardless of the substrate type. Also, a small line edge roughness (LER) is one of the important performances to be emphasized.

[0004] Regarding the control of sensitivity and pattern profile, various improvements have been made by selecting, combining, and processing conditions of the materials used in the resist composition. As one of such improvements, there is an inhibition of acid diffusion that has an important influence on the resolution of the resist film. When processing a photomask, it is desired that the shape of the resist pattern to be obtained does not change depending on the time from exposure until heating. A major cause of the time-dependent change in the resist pattern shape is the diffusion of the acid generated by exposure. This problem of acid diffusion has a significant impact on sensitivity and resolution not only in photomask processing but also in general resist compositions, and thus there have been many studies.

[0005] Patent Document 1 and Patent Document 2 describe examples of suppressing acid diffusion and reducing LER by making the acid generated from an acid generator bulky. However, such an acid generator has insufficient inhibition of acid diffusion, and it is desired to develop an acid generator with smaller diffusion.

[0006] Further, Patent Document 3 describes an example in which a repeating unit having a sulfonium structure that generates sulfonic acid upon exposure is introduced into a polymer used in a resist composition to control acid diffusion. Such a method of introducing a repeating unit that generates acid upon exposure into a base polymer to suppress acid diffusion is effective as a method for obtaining a pattern with small LER. However, there are cases where a base polymer containing such a repeating unit that generates acid upon exposure has problems with solubility in organic solvents depending on the structure and introduction rate of the unit.

[0007] Polymers having a large amount of aromatic skeletons with acidic side chains, such as polyhydroxystyrene, are useful as base polymers for KrF lithography resist compositions, but cannot be used as base polymers for ArF lithography resist compositions because of their high absorption of light near a wavelength of 200 nm. However, as a powerful technology for forming a pattern smaller than the processing limit achieved by using ArF excimer laser, i.e., for EB lithography resist compositions and EUV lithography resist compositions, it is an important material in terms of obtaining high etching resistance.

[0008] As the base polymer for positive EB lithography resist compositions and EUV lithography resist compositions, materials that use the acid generated by irradiating a photoacid generator with high-energy rays as a catalyst to deprotect acid-labile groups that cover the acidic functional groups of the phenol side chains of the base polymer and are thus soluble in an alkaline developer are mainly used. Further, the aforementioned acid-labile groups mainly use tertiary alkyl groups, tert-butoxycarbonyl groups, acetal groups, etc. Here, if an acid-labile group that requires less activation energy for deprotection, such as an acetal group, is used, there is an advantage of obtaining a highly sensitive resist film, but when the suppression of acid diffusion generated is insufficient, a deprotection reaction occurs even in the unexposed portion of the resist film, resulting in problems of deterioration in resolution and LER.

[0009] On the other hand, in the development step of photomask manufacturing, a so-called development loading phenomenon is known, in which the final pattern sizes on the photomask differ between areas with dense patterns and sparse areas. That is, due to development loading, the final pattern sizes are unevenly distributed according to the surrounding pattern distribution. The causes can include differences in the dissociation reaction during acid generation due to differences in the energy of the electron beam (EB), and differences in the dissolution rate of the dense and sparse pattern drawing portions in the alkaline developer solution. As one of the improvement methods, Patent Document 4 discloses a method of adjusting the incident dose in an EB drawing apparatus to irradiate the EB and perform pattern drawing on the photomask in order to correct development loading. However, the conventional correction methods do not sufficiently consider the phenomenon of development loading for correction. Therefore, the correction accuracy of the conventional correction methods for development loading is poor. To solve this problem, the drawing methods during the drawing of the resist film and the method of improving the development method after patterning described in Patent Documents 5 and 6 have been developed, but in advanced generations, the uniform distribution of fine dense and sparse patterns is not yet satisfactory, and it is desired to improve the resist composition.

[0010] Prior Art Documents

[0011] Patent Documents

[0012] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2009-053518

[0013] [Patent Document 2] Japanese Unexamined Patent Application Publication No. 2010-100604

[0014] [Patent Document 3] Japanese Unexamined Patent Application Publication No. 2011-22564

[0015] [Patent Document 4] Japanese Unexamined Patent Application Publication No. 2007-150243

[0016] [Patent Document 5] Japanese Patent No. 5443548

[0017] [Patent Document 6] Japanese Patent No. 6281244 Summary of the Invention

[0018] Problems to be Solved by the Invention

[0019] The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a chemically amplified positive resist composition capable of forming a resist film having extremely high resolution, small line edge roughness (LER), excellent rectangularity, and suppressed influence of development loading, and a resist pattern forming method using the chemically amplified positive resist composition.

[0020] Means for Solving the Problems

[0021] The inventors of the present application have made intensive studies to achieve the aforementioned object, and as a result, it has been found that: by introducing a base polymer having a specific structure into a resist composition, a pattern having good resolution, pattern shape, and LER and having an influence of development load suppressed can be obtained, and thus the present invention has been completed.

[0022] That is, the present invention provides the following chemically amplified positive resist composition and resist pattern forming method.

[0023] 1. A chemically amplified positive resist composition containing a base polymer protected by an acid-labile group and becoming alkali-soluble by the action of an acid,

[0024] The base polymer includes a polymer containing an acid-generating unit, a phenolic hydroxyl group-containing unit, a unit in which the phenolic hydroxyl group is protected by an acid-labile group, and a unit in which a carboxyl group is protected by an acid-labile group, or a polymer including an acid-generating unit, a phenolic hydroxyl group-containing unit, and a unit in which the phenolic hydroxyl group is protected by an acid-labile group and a polymer containing an acid-generating unit, a phenolic hydroxyl group-containing unit, and a unit in which a carboxyl group is protected by an acid-labile group.

[0025] The acid-generating unit is a repeating unit represented by any one of the following formulas (A1) to (A8),

[0026] The phenolic hydroxyl group-containing unit is a repeating unit represented by the following formula (B1),

[0027] The unit in which the phenolic hydroxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (B2),

[0028] The unit in which the carboxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (B3),

[0029] In all the repeating units of the polymer contained in the base polymer, the repeating units having an aromatic ring skeleton are 60 mol% or more;

[0030] [Chemical formula 1]

[0031]

[0032] In the formula, R A are each independently a hydrogen atom or a methyl group;

[0033] X 1 is a single bond, an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining them, or *-O-X 11 -, *-C(=O)-O-X 11 -, or *-C(=O)-NH-X 11 -, X 11is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining them, and may also contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group;

[0034] X 2 is a single bond or **-X 21 -C(=O)-O-, X 21 is an alkylene group having 1 to 20 carbon atoms that may also contain a heteroatom;

[0035] X 3 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, *-O-X 31 -, *-C(=O)-O-X 31 - or *-C(=O)-NH-X 31 -, X 31 is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a group having 7 to 20 carbon atoms obtained by combining them, and may also contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group;

[0036] * is an atomic bond between the carbon atom of the main chain, and ** is an atomic bond between the oxygen atom in the formula;

[0037] X 4 is a single bond or an alkylene group having 1 to 30 carbon atoms that may also contain a heteroatom;

[0038] k 1 and k 2 each independently is 0 or 1, provided that when X 4 is a single bond, k 1 and k 2 are 0;

[0039] R 1 ~R 18 each independently is a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms that may also contain a heteroatom; further, R 1 and R 2 may also bond to each other and together with the sulfur atom to which they are bonded form a ring,

[0040] R 3 and R 4 、R 6 and R 7 、or R 9 and R 10 may also bond to each other and together with the sulfur atom to which they are bonded form a ring,

[0041] R HF is a hydrogen atom or a trifluoromethyl group;

[0042] Xa -is a non-nucleophilic relative ion;

[0043] [Chemical formula 2]

[0044]

[0045] In the formula, R B is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0046] R 21 is a halogen atom, a saturated hydrocarbon carbonyloxy group with 2 to 8 carbon atoms that may be substituted by a halogen atom, a saturated hydrocarbon group with 1 to 6 carbon atoms that may be substituted by a halogen atom, or a saturated hydrocarbon oxy group with 1 to 6 carbon atoms that may be substituted by a halogen atom,

[0047] Y 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, where * is the atomic bond between the carbon atom of the main chain;

[0048] A 1 is a single bond or a saturated alkylene group with 1 to 10 carbon atoms, and a part of -CH2- constituting the saturated alkylene group may also be substituted by -O-;

[0049] a is an integer satisfying 0 ≤ a ≤ 5 + 2c - b;

[0050] b is an integer from 1 to 3,

[0051] c is an integer from 0 to 2.

[0052] [Chemical formula 3]

[0053]

[0054] In the formula, R B is the same as described above.

[0055] R 22 is a halogen atom, a saturated hydrocarbon carbonyloxy group with 2 to 8 carbon atoms that may be substituted by a halogen atom, a saturated hydrocarbon group with 1 to 6 carbon atoms that may be substituted by a halogen atom, or a saturated hydrocarbon oxy group with 1 to 6 carbon atoms that may be substituted by a halogen atom,

[0056] Y 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, where * is the atomic bond between the carbon atom of the main chain,

[0057] A 2 is a single bond or a saturated alkylene group with 1 to 10 carbon atoms, and a part of -CH2- constituting the saturated alkylene group may also be substituted by -O-,

[0058] R 23It is an acid-labile group when e is 1, and is a hydrogen atom or an acid-labile group when e is 2 or more, with at least one being an acid-labile group;

[0059] d is an integer satisfying 0 ≤ d ≤ 5 + 2f - e;

[0060] e is an integer from 1 to 3;

[0061] f is an integer from 0 to 2;

[0062] [Chemical formula 4]

[0063]

[0064] In the formula, R B is the same as described above,

[0065] Y 3 is a single bond, phenylene or naphthylene, or a linking group having 1 to 12 carbon atoms with an ester bond, an ether bond or a lactone ring;

[0066] R 24 is an acid-labile group.

[0067] 2. The chemically amplified positive resist composition according to 1., wherein,

[0068] The acid-generating unit is a repeating unit represented by the following formula (A4),

[0069] The unit containing a phenolic hydroxyl group is a repeating unit represented by the following formula (B1-1),

[0070] The unit in which the phenolic hydroxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (B2-1),

[0071] The unit in which the carboxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (B3-1);

[0072] [Chemical formula 5]

[0073]

[0074] In the formula, R A , R B , X 4 , R 9 , R 10 , R 11 , b and k 1 are the same as described above,

[0075] Y 3A is a single bond, phenylene or naphthylene,

[0076] R 25 and R 26Each independently is an acid-labile group having an aromatic hydrocarbon group with 6 to 20 carbon atoms and / or an alicyclic hydrocarbon group with 5 to 20 carbon atoms.

[0077] 3. The chemically amplified positive resist composition according to 2., wherein the base polymer comprises a polymer containing a repeating unit represented by formula (A4), a repeating unit represented by (B1-1), a repeating unit represented by (B2-1), and a repeating unit represented by (B3-1).

[0078] 4. The chemically amplified positive resist composition according to any one of 1. to 3., wherein the polymer contained in the base polymer further contains a repeating unit represented by any one of the following formulas (C1) to (C3);

[0079] [Chemical Formula 6]

[0080]

[0081] In the formula, R B is the same as described above.

[0082] g and h are each independently an integer from 0 to 4,

[0083] i is an integer from 0 to 5,

[0084] j is an integer from 0 to 2,

[0085] R 31 and R 32 are each independently a hydroxyl group, a halogen atom, a saturated hydrocarbon carbonyloxy group with 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group with 1 to 8 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbon oxy group with 1 to 8 carbon atoms which may be substituted by a halogen atom,

[0086] R 33 is an acetyl group, a saturated hydrocarbon group with 1 to 20 carbon atoms, a saturated hydrocarbon oxy group with 1 to 20 carbon atoms, a saturated hydrocarbon carbonyloxy group with 2 to 20 carbon atoms, a saturated hydrocarbon oxyhydrocarbon group with 2 to 20 carbon atoms, a saturated hydrocarbon sulfhydrocarbon group with 2 to 20 carbon atoms, a halogen atom, a nitro group or a cyano group, and may also be a hydroxyl group when j is 1 or 2,

[0087] Y 4 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, where * is an atomic bond between the carbon atom of the main chain,

[0088] A 3 is a single bond, or a saturated alkylene group with 1 to 10 carbon atoms, and a part of -CH2- constituting the saturated alkylene group may also be substituted by -O-.

[0089] 5. The chemically amplified positive resist composition according to any one of 1. to 4., wherein,

[0090] The base polymer further comprises a polymer containing a repeating unit represented by the following formula (B1) and at least one selected from the repeating units represented by the following formula (B2) and the repeating unit represented by the following formula (B3), and not containing the repeating units represented by the formulas (A1) to (A8).

[0091] 6. The chemically amplified positive resist composition according to any one of 1. to 5., further comprising a polymer containing a fluorine atom, the polymer containing a fluorine atom containing at least one selected from the repeating unit represented by the following formula (D3), the repeating unit represented by the following formula (D4), the repeating unit represented by the following formula (D5), and the repeating unit represented by the following formula (D6), and may further contain at least one selected from the repeating unit represented by the following formula (D1) and the repeating unit represented by the following formula (D2);

[0092] [Chemical formula 7]

[0093]

[0094] In the formula, R C are each independently a hydrogen atom or a methyl group,

[0095] R D are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0096] R 101 is a hydrogen atom, or a linear or branched hydrocarbon group having 1 to 5 carbon atoms in which a heteroatom-containing group may be inserted between carbon-carbon bonds,

[0097] R 102 is a linear or branched hydrocarbon group having 1 to 5 carbon atoms in which a heteroatom-containing group may be inserted between carbon-carbon bonds,

[0098] R 103 is a saturated hydrocarbon group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, and a part of -CH2- constituting the saturated hydrocarbon group may be substituted with an ester bond or an ether bond,

[0099] R 104 , R 105 , R 107 and R 108 are each independently a hydrogen atom or a saturated hydrocarbon group having 1 to 10 carbon atoms,

[0100] R 106 , R 109 , R 110 and R 111 are each independently a hydrogen atom, a hydrocarbon group having 1 to 15 carbon atoms, a fluorinated hydrocarbon group having 1 to 15 carbon atoms or an acid-labile group, R 106 , R 109 , R 110 and R 111When it is a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group may also be inserted between carbon-carbon bonds;

[0101] x is an integer from 1 to 3,

[0102] y is an integer satisfying 0 ≤ y ≤ 5 + 2z - x,

[0103] z is 0 or 1,

[0104] m is an integer from 1 to 3,

[0105] Z 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, where * is the atomic bond between the carbon atom of the main chain,

[0106] Z 2 is a single bond, -O-, *-C(=O)-O-Z 21 -Z 22 - or *-C(=O)-NH-Z 21 -Z 22 -, Z 21 is a single bond or a saturated alkylene group with 1 to 10 carbon atoms, Z 22 is a single bond, an ester bond, an ether bond or a sulfonamide bond, where * is the atomic bond between the carbon atom of the main chain,

[0107] Z 3 is a (m + 1)-valent hydrocarbon group with 1 to 20 carbon atoms or a (m + 1)-valent fluorinated hydrocarbon group with 1 to 20 carbon atoms.

[0108] 7. The chemically amplified positive resist composition according to any one of 1. to 6., further comprising an organic solvent.

[0109] 8. The chemically amplified positive resist composition according to any one of 1. to 7., further comprising a photoacid generator.

[0110] 9. The chemically amplified positive resist composition according to 8., wherein the acid strength (pKa) of the anion of the photoacid generator is -2.0 or more.

[0111] 10. The chemically amplified positive resist composition according to any one of 1. to 9., wherein the dissolution rate of the overexposed portion of the resist film obtained from the chemically amplified positive resist composition is 50 nm / sec or more.

[0112] 11. A method for forming a resist pattern, comprising the following steps:

[0113] Forming a resist film on a substrate using the chemically amplified positive resist composition according to any one of 1. to 10.,

[0114] Irradiating the resist film with high-energy rays to form a pattern, and,

[0115] The resist film having the irradiated pattern is developed using an alkaline developer.

[0116] 12. The resist pattern forming method according to 11., wherein the high-energy ray is extreme ultraviolet ray or electron beam.

[0117] 13. The resist pattern forming method according to 11. or 12., wherein the outermost surface of the substrate is made of a material containing at least one selected from chromium, silicon, tantalum, molybdenum, cobalt, nickel, tungsten, and tin.

[0118] 14. The resist pattern forming method according to any one of 11. to 13., wherein the substrate is a blank photomask.

[0119] 15. A blank photomask coated with the chemically amplified positive resist composition according to any one of 1. to 10.

[0120] Effects of the Invention

[0121] The chemically amplified positive resist composition of the present invention can form a pattern with high resolution, small LER, good shape after exposure, and a pattern in which the influence of development load is suppressed, and is suitable as a resist composition for a resist film for forming high-energy rays such as ultraviolet rays, far ultraviolet rays, EB, EUV, X-rays, γ-rays, synchrotron radiation, etc. used in the processing of inductive semiconductors, blank photomasks, etc. Further, the pattern forming method using the chemically amplified positive resist composition of the present invention can form a pattern with high resolution and reduced LER and a pattern in which the influence of development load is suppressed, so it is suitable for microfabrication techniques, particularly EUV lithography and EB lithography. Detailed Description

[0122] The present invention will be described in detail below. Further, in the following description, depending on the structure represented by the chemical formula, there may be an asymmetric carbon and there may be enantiomers and diastereomers. In this case, these isomers are represented by one general formula. These isomers may be used alone or in the form of a mixture.

[0123] [Chemically Amplified Positive Resist Composition]

[0124] The chemically amplified positive resist composition of the present invention contains a base polymer protected by an acid-labile group and made alkali-soluble by the action of an acid.

[0125] The aforementioned base polymer includes a polymer containing an acid generating unit, a unit having a phenolic hydroxyl group, a unit in which the phenolic hydroxyl group is protected by an acid-labile group, and a unit in which a carboxyl group is protected by an acid-labile group, or a polymer containing an acid generating unit, a unit having a phenolic hydroxyl group, and a unit in which the phenolic hydroxyl group is protected by an acid-labile group, and a polymer containing an acid generating unit, a unit having a phenolic hydroxyl group, and a unit in which a carboxyl group is protected by an acid-labile group.

[0126] The aforementioned acid generating unit is a repeating unit represented by any one of the following formulas (A1) to (A8) (hereinafter also referred to as repeating units A1 to A8, respectively).

[0127] [Chemical formula 8]

[0128]

[0129] In formulas (A1) to (A8), R A are each independently a hydrogen atom or a methyl group. X 1 is a single bond, an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining them, or *-O-X 11 -, *-C(=O)-O-X 11 -, or *-C(=O)-NH-X 11 -, X 11 is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining them, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. X 2 is a single bond or **-X 21 -C(=O)-O-, X 21 is an alkylene group having 1 to 20 carbon atoms that may also contain a heteroatom. X 3 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, *-O-X 31 -, *-C(=O)-O-X 31 -, or *-C(=O)-NH-X 31 -. X 31 is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a group having 7 to 20 carbon atoms obtained by combining them, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. * is an atomic bond between the carbon atom of the main chain, and ** is an atomic bond between the oxygen atom in the formula. X 4 is a single bond or an alkylene group having 1 to 30 carbon atoms that may also contain a heteroatom. k 1 and k 2 are each independently 0 or 1, provided that when X 4 is a single bond, k 1 and k 2is 0.

[0130] The repeating unit represented by formula (A4) or (A8) is a repeating unit in which, when irradiated with high-energy rays such as ultraviolet rays, far ultraviolet rays, EB, EUV, X-rays, γ-rays, synchrotron radiation, etc., an acid in which the β-position of the sulfonyl group is difluoromethylated is generated. The aforementioned acid has an acid strength capable of deprotecting a polymer having a unit in which a phenolic hydroxyl group is protected by an acetal group, a tertiary alkyl group, a tert-butoxycarbonyl group, etc. Further, if a polymer containing the aforementioned repeating unit is used as a base polymer of a resist composition, the movement and diffusion of the generated acid can be moderately controlled.

[0131] Photoacid generators that generate arene sulfonic acid upon irradiation with high-energy rays are also often used to deprotect polymers having units in which phenolic hydroxyl groups are protected by acetal groups, tertiary alkyl groups, or tert-butoxycarbonyl groups. However, even when an arene sulfonic acid generating unit is introduced into the repeating unit of the base polymer in order to obtain the effects of the present invention, the base polymer may sometimes be insoluble in the solvent due to its low solvent solubility. On the other hand, the polymer containing the repeating unit represented by formula (A4) or (A8) of the present invention has sufficient lipophilicity, so its production and operation are easy, and the preparation of the resist composition is also easy.

[0132] In formulas (A2) and (A6), X 2 is -X 21 In the case of -C(=O)-O-, X 21 Examples of the alkylene group which may contain a hetero atom represented include, but are not limited to, the following.

[0133] [Chemical formula 9]

[0134]

[0135] In the formula, the dotted line is an atomic bond.

[0136] In formulas (A2) and (A6), R HF is a hydrogen atom or a trifluoromethyl group. In the repeating units A2 and A6, specific examples when R HF is a hydrogen atom can be those described in Japanese Patent Laid-Open No. 2010-116550, and specific examples when R HF is a trifluoromethyl group can be those described in Japanese Patent Laid-Open No. 2010-77404. The repeating units A3 and A7 can be those described in Japanese Patent Laid-Open No. 2012-246265 and Japanese Patent Laid-Open No. 2012-246426.

[0137] In formulas (A1) and (A5), Xa - is a non-nucleophilic counter ion. Xa -A non-nucleophilic relative ion represented, for example, by those described in JP-A-2010-113209 and JP-A-2007-145797.

[0138] X 4 An alkylene group having 1 to 30 carbon atoms which may also contain a heteroatom, which may be saturated or unsaturated, and which may be linear, branched or cyclic. Specific examples thereof include methanediyl, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, heptadecane-1,17-diyl and other alkanediyl groups; cyclopentanediyl, cyclohexanediyl, norbornanediyl, adamantanediyl and other cycloaliphatic saturated alkylene groups; phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, n-propylnaphthylene, isopropylnaphthylene, n-butylnaphthylene, isobutylnaphthylene, sec-butylnaphthylene, tert-butylnaphthylene and other arylene groups; groups obtained by combining these; and the like.

[0139] Furthermore, part or all of the hydrogen atoms of the aforementioned alkylene group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and part of -CH2- constituting the aforementioned alkylene group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride, a haloalkyl group or the like may be formed.

[0140] Preferable examples of the anions of the monomers providing the repeating units A4 and A8 are shown below, but are not limited thereto.

[0141] [Chemical formula 10]

[0142]

[0143] [Chemical formula 11]

[0144]

[0145] In formulas (A1) to (A8), R 1 ~R 18 are each independently a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom.

[0146] Examples of the foregoing halogen atoms include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.

[0147] The hydrocarbon group having 1 to 20 carbon atoms may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a n-butyl group, a sec-butyl group, a tert-butyl group, a tert-pentyl group, a n-pentyl group, a n-hexyl group, a n-octyl group, a 2-ethylhexyl group, a n-nonyl group, a n-decyl group; cycloalkyl saturated hydrocarbon groups having 3 to 20 carbon atoms such as a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, a tricyclo[5.2.1.0 2,6 decyl group, an adamantyl group, an adamantylmethyl group; aryl groups having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, an anthryl group, etc. Further, a part or all of the hydrogen atoms of the foregoing hydrocarbon group may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc. may be inserted between the carbon-carbon bonds of the foregoing hydrocarbon group. As a result, it may also contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride, a haloalkyl group, etc.

[0148] Further, R 1 and R 2 may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. R 3 and R 4 , R 6 and R 7 , or R 9 and R 10 may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. Examples of the ring formed at this time include those shown below, etc.

[0149] [Chemical formula 12]

[0150]

[0151] [[ID=3q]]In the formula, the dotted line represents an atomic bond.

[0152] In formulas (A2) to (A4), specific structures of the sulfonium cation include, but are not limited to, the following.

[0153] [Chemical formula 13]

[0154]

[0155] [Chemical formula 14]

[0156]

[0157] [Chemical formula 15]

[0158]

[0159] [Chemical Formula 16]

[0160]

[0161] [Chemical Formula 17]

[0162]

[0163] [Chemical Formula 18]

[0164]

[0165] [Chemical Formula 19]

[0166]

[0167] [Chemical Formula 20]

[0168]

[0169] [Chemical Formula 21]

[0170]

[0171] [Chemical Formula 22]

[0172]

[0173] [Chemical Formula 23]

[0174]

[0175] [Chemical Formula 24]

[0176]

[0177] [Chemical Formula 25]

[0178]

[0179] [Chemical Formula 26]

[0180]

[0181] [Chemical Formula 27]

[0182]

[0183] [Chemical Formula 28]

[0184]

[0185] [Chemical Formula 29]

[0186]

[0187] [Chemical Formula 30]

[0188]

[0189] [Chemical Formula 31]

[0190]

[0191] [Chemical Formula 32]

[0192]

[0193] [Chemical Formula 33]

[0194]

[0195] [Chemical Formula 34]

[0196]

[0197] In formulas (A5) to (A8), specific structures of the sulfonium cations are exemplified below, but are not limited to these.

[0198] [Chemical Formula 35]

[0199]

[0200] [Chemical Formula 36]

[0201]

[0202] Among the repeating units A1 to A8, the repeating unit A4 can be exemplified in view of the acid strength of the acid leaving group of the polymer being optimal for the processing of the blank photomask.

[0203] The repeating units A1 to A8 are units that generate acid upon irradiation with high-energy rays. By containing such units in the polymer, it is considered that acid diffusion is moderately suppressed, and a pattern with reduced LER can be obtained. Also, by containing such units in the polymer, the phenomenon in which acid volatilizes from the exposed portion and reattaches to the unexposed portion during baking in a vacuum is suppressed, and it is considered to be effective in reducing LER and reducing shape deterioration due to unwanted film loss in the unexposed portion.

[0204] The repeating units A1 to A8 are preferably introduced in the range of 0.1 to 30 mol%, more preferably in the range of 0.5 to 20 mol%, based on all the repeating units of the polymer to be contained in the base polymer. The repeating units A1 to A8 can be used alone or in combination of two or more.

[0205] The unit containing a phenolic hydroxyl group described above is a repeating unit represented by the following formula (B1) (hereinafter also referred to as repeating unit B1).

[0206] [Chemical formula 37]

[0207]

[0208] In formula (B1), R B is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0209] In formula (B1), R 21 is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbon oxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom. The saturated hydrocarbon group, the saturated hydrocarbon carbonyloxy group, and the saturated hydrocarbon base of the saturated hydrocarbon oxy group may be linear, branched, or cyclic, and specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, pentyl, and hexyl; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; groups obtained by combining these, etc. When the number of carbon atoms is below the upper limit, the solubility in an alkaline developer is good. When a is 2 or more, each R 21 may be the same or different from each other.

[0210] In formula (B1), Y 1 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * is an atomic bond between the carbon atom of the main chain.

[0211] In formula (B1), A 1 is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a part of -CH2- constituting the saturated alkylene group may be substituted by -O-. The saturated alkylene group may be linear, branched, or cyclic, and specific examples thereof include alkanediyl groups having 1 to 10 carbon atoms such as methylene, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, and structural isomers thereof; cycloalkanediyl groups having 3 to 10 carbon atoms such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, and cyclohexanediyl; groups obtained by combining these, etc.

[0212] In formula (B1), a is an integer satisfying 0 ≤ a ≤ 5 + 2c - b. b is an integer of 1 to 3. c is an integer of 0 to 2.

[0213] Y 1 and A 1 are both single bonds, and ideal examples of the repeating unit B1 may include units derived from 3-hydroxystyrene, 4-hydroxystyrene, 5-hydroxy-2-vinylnaphthalene, 6-hydroxy-2-vinylnaphthalene, etc. Among them, a repeating unit represented by the following formula (B1-1) etc. is more preferable.

[0214] [Chemical formula 38]

[0215]

[0216] In the formula, R B and b are the same as described above.

[0217] Y 1 In the case of other than a single bond, ideal examples of the repeating unit B1 are listed below but are not limited to these. Also, in the following formula, R B is the same as described above.

[0218] [Chemical formula 39]

[0219]

[0220] [Chemical formula 40]

[0221]

[0222] It is preferable to introduce the repeating unit B1 in the range of 10 to 95 mol% in all the repeating units of the polymer contained in the base polymer, and more preferably in the range of 30 to 85 mol%. However, when containing at least one or more of the repeating units represented by the formulas (B3) and (B4) which provide higher etching resistance to the polymer used in the present invention described later and this unit has a phenolic hydroxyl group as a substituent, it is also preferable to add this ratio and be within the above range. The repeating unit B1 can be used alone or in combination of two or more.

[0223] The unit in which the phenolic hydroxyl group is protected by an acid-labile group is the repeating unit represented by the following formula (B2) (hereinafter also referred to as the repeating unit B2).

[0224] [Chemical formula 41]

[0225]

[0226] In the formula (B2), R B is the same as described above. R 22 is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbon oxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom. The saturated hydrocarbon group, and the saturated hydrocarbon base of the saturated hydrocarbon carbonyloxy group and the saturated hydrocarbon oxy group may be linear, branched, or cyclic, and specific examples thereof can be listed as the same as those exemplified in the description of R 21 in the formula (B1). When the number of carbon atoms is below the upper limit, the solubility in the alkali developing solution is good. When d is 2 or more, each R 22 may be the same or different from each other.

[0227] In formula (B2), Y 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is a bond between an atom and a carbon atom of the main chain.

[0228] In formula (B2), A 2 is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a part of -CH2- constituting the saturated alkylene group may be replaced by -O-. The saturated alkylene group may be linear, branched or cyclic, and specific examples thereof are the same as those exemplified for A 1 in formula (B1).

[0229] In formula (B2), R 23 is an acid-labile group when e = 1, and is a hydrogen atom or an acid-labile group when e ≥ 2, but at least one of them is an acid-labile group.

[0230] In formula (B2), d is an integer satisfying 0 ≤ d ≤ 5 + 2f - e. e is an integer of 1 to 3. f is an integer of 0 to 2.

[0231] The unit in which the carboxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (B3) (hereinafter also referred to as repeating unit B3).

[0232] [Chemical formula 42]

[0233]

[0234] In formula (B3), R B is the same as described above. Y 3 is a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 12 carbon atoms having an ester bond, an ether bond or a lactone ring. R 24 is an acid-labile group.

[0235] R 23 and R 24 The acid-labile groups represented by can be used without particular limitation as long as they are those that provide an acidic group by acid dissociation and have been used in many known chemically amplified resist compositions.

[0236] The repeating unit B2 is obtained by replacing the hydrogen atom of the phenolic hydroxyl group with an acid-labile group, and it is particularly preferable that the hydrogen atom of the hydroxyl group of hydroxystyrene or hydroxyphenyl (meth)acrylate is replaced with an acid-labile group. Monomers providing the repeating unit B2 are listed below but are not limited to these. Also, in the following formula, R B and R 23 are the same as described above.

[0237] [Chemical formula 43]

[0238]

[0239] Further, the repeating unit B3 is obtained by substituting the hydrogen atom of a carboxyl group with an acid-labile group, and it is particularly preferable that the hydrogen atom of the hydroxyl group of a (meth)acrylate is substituted with an acid-labile group. Monomers that provide the repeating unit B3 are listed below but are not limited to these. Further, in the following formula, R B and R 24 are the same as described above.

[0240] [Chemical formula 44]

[0241]

[0242] [Chemical formula 45]

[0243]

[0244] R 23 and R 24 Examples of the acid-labile group represented include those described in paragraphs

[0030] to

[0082] of Japanese Unexamined Patent Application Publication No. 2014-219657.

[0245] The aforementioned acid-labile group is preferably represented by the following formulas (AL-1) to (AL-19).

[0246] [Chemical formula 46]

[0247]

[0248] In formulas (AL-1) to (AL-19), R L1 are each independently a saturated hydrocarbon group or an aryl group having 6 to 20 carbon atoms. R L2 and R L4 are each independently a hydrogen atom or a saturated hydrocarbon group having 1 to 20 carbon atoms. R[[ID=4�]] L3 is an aryl group having 6 to 20 carbon atoms. The aforementioned saturated hydrocarbon group may be linear, branched, or cyclic. Further, the aforementioned aryl group is preferably a phenyl group or the like. R F is a fluorine atom or a trifluoromethyl group. n is an integer from 1 to 5.

[0249] If a tertiary hydrocarbon group is selected as the aforementioned acid-labile group, when forming a resist film with a thickness of, for example, 10 to 100 nm and forming a fine pattern with a line width of 45 nm or less, it is still possible to provide a pattern with small LER, so it is ideal. For the aforementioned tertiary hydrocarbon group, in order to obtain the monomer for polymerization by distillation, it is preferably a group having 4 to 18 carbon atoms. Further, examples of the group bonded to the tertiary carbon atom of the aforementioned tertiary hydrocarbon group include a saturated hydrocarbon group having 1 to 20 carbon atoms that may contain an oxygen atom-containing functional group such as an ether bond or a carbonyl group, and the groups bonded to the aforementioned tertiary carbon atom can also bond to each other to form a ring. [[ID=]]

[0250] Specific examples of the group bonded to the tertiary carbon atom include methyl, ethyl, propyl, adamantyl, norbornyl, tetrahydrofuran-2-yl, 7-oxanorbornane-2-yl, cyclopentyl, 2-tetrahydrofuranyl, tricyclo[5.2.1.0 2,6 decyl, tetracyclo[4.4.0.1 2,5 .1 7,10 dodecyl, 3-oxo-1-cyclohexyl.

[0251] Examples of the aforementioned tertiary hydrocarbon group include: tert-butyl, tert-pentyl, 1-ethyl-1-methylpropyl, 1,1-diethylpropyl, 1,1,2-trimethylpropyl, 1-adamantyl-1-methylethyl, 1-methyl-1-(2-norbornyl)ethyl, 1-methyl-1-(tetrahydrofuran-2-yl)ethyl, 1-methyl-1-(7-oxanorbornane-2-yl)ethyl, 1-methylcyclopentyl, 1-ethylcyclopentyl, 1-propylcyclopentyl, 1-isopropylcyclopentyl, 1-cyclopentylcyclopentyl, 1-cyclohexylcyclopentyl, 1-(2-tetrahydrofuranyl)cyclopentyl, 1-(7-oxanorbornane-2-yl)cyclopentyl, 1-methylcyclohexyl, 1-ethylcyclohexyl, 1-isopropylcyclohexyl, 1-cyclopentylcyclohexyl, 1-cyclohexylcyclohexyl, 2-methyl-2-norbornyl, 2-ethyl-2-norbornyl, 8-methyl-8-tricyclo[5.2.1.0 2 ,6 decyl, 8-ethyl-8-tricyclo[5.2.1.0 2,6 decyl, 3-methyl-3-tetracyclo[4.4.0.1 2,5 .1 7,10 dodecyl, 3-ethyl-3-tetracyclo[4.4.0.1 2,5 .1 7,10 dodecyl, 3-isopropyl-3-tetracyclo[4.4.0.1 2,5 .1 7,10 dodecyl, 2-methyl-2-adamantyl, 2-ethyl-2-adamantyl, 2-isopropyl-2-adamantyl, 1-methyl-3-oxo-1-cyclohexyl, 1-methyl-1-(tetrahydrofuran-2-yl)ethyl, 5-hydroxy-2-methyl-2-adamantyl, 5-hydroxy-2-ethyl-2-adamantyl, 2-(4-fluorophenyl)-2-propyl, etc.

[0252] Furthermore, the acetal group represented by the following formula (AL-20) is often used as an acid-labile group and is a useful option as an acid-labile group that stably provides a more rectangular pattern at the interface between the pattern and the substrate.

[0253] [Chemical Formula 47]

[0254]

[0255] In formula (AL-20), R L5 is a hydrogen atom or a saturated hydrocarbon group having 1 to 10 carbon atoms. L6 It is a saturated hydrocarbon group having 1 to 30 carbon atoms.

[0256] R L5 The degradable group can be appropriately selected according to the design of the acid sensitivity. For example, if the design is to decompose with a strong acid to ensure high stability, a hydrogen atom can be selected. If the design is to use high reactivity and high sensitivity to pH changes, a straight-chain alkyl group can be selected. Although it also depends on the combination of the acid generator and the basic compound added to the resist composition, when R L6 For designs with relatively large alkyl substitution at the end, R L5 Preferably, the carbon bonded to the acetal carbon is a secondary carbon atom. L5 Examples of include isopropyl, sec-butyl, cyclopentyl, and cyclohexyl.

[0257] Among the aforementioned acetal groups, in order to obtain higher resolution, R L6 It is preferably a polycyclic alkyl group having 7 to 30 carbon atoms. L6 In the case of a polycyclic alkyl group, it is preferred that a bond is formed between the secondary carbon atoms constituting the polycyclic ring structure and the acetal oxygen. When the bond is formed on a secondary carbon atom of the ring structure, the polymer becomes a more stable compound than when the bond is formed on a tertiary carbon atom, and the storage stability of the resist composition becomes good without deteriorating the resolution. In addition, compared to R L6 When the polymer is bonded to the primary carbon atom into which a linear alkyl group having 1 or more carbon atoms is inserted, the glass transition temperature (Tg) of the polymer becomes favorable, and the resist pattern after development does not suffer from shape defects due to baking.

[0258] Preferred examples of the group represented by formula (AL-20) include the following, but are not limited thereto. L5 Same as above.

[0259] [Chemistry 48]

[0260]

[0261] The repeating unit B2 is preferably represented by the following formula (B2-1), and the repeating unit B3 is preferably represented by the following formula (B3-1).

[0262] [Chemistry 49]

[0263]

[0264] Where R B Same as above. Y 3Ais a single bond, a phenylene group or a naphthylene group. R 25 and R 26 are each independently an acid-labile group having an aromatic hydrocarbon group with 6 to 20 carbon atoms and / or an alicyclic hydrocarbon group with 5 to 20 carbon atoms.

[0265] It is preferable to introduce the repeating unit B2 in the range of 2 to 40 mol% among all the repeating units of the polymer contained in the base polymer, and it is preferable to introduce the repeating unit B3 in the range of 2 to 40 mol% among all the repeating units of the polymer contained in the base polymer. It is preferable to introduce the repeating units B2 and B3 in total in the range of 5 to 60 mol% among all the repeating units of the polymer contained in the base polymer.

[0266] Regarding the design of the aforementioned base polymer, by designing to protect two kinds of phenolic hydroxyl groups and carboxyl groups with acid-labile groups and then mixing them, since the phenolic skeleton maintains the pattern straightness, and at the same time the dissolution rate of the exposed part is increased by using the carboxylic acid ester skeleton, good resolution of the exposed part can be maintained and the dissolution contrast between the exposed part and the unexposed part can be optimized. Therefore, a pattern with suppressed influence of development load, independent of pattern density, and small size difference can be obtained. When manufacturing a photomask, compared with processing a wafer substrate, the development conditions are stronger, so a pattern with good resolution and small size difference with suppressed influence of development load is required. The chemically amplified positive resist composition of the present invention is particularly suitable for processing a photomask substrate.

[0267] It is preferable that the polymer contained in the aforementioned base polymer further contains at least one selected from the repeating unit represented by the following formula (C1) (hereinafter also referred to as repeating unit C1), the repeating unit represented by the following formula (C2) (hereinafter also referred to as repeating unit C2), and the repeating unit represented by the following formula (C3) (hereinafter also referred to as repeating unit C3).

[0268] [Chemical formula 50]

[0269]

[0270] In formulas (C1) and (C2), g and h are each independently an integer of 0 to 4.

[0271] In formulas (C1) and (C2), R 31 and R 32 are each independently a hydroxyl group, a halogen atom, a saturated hydrocarbon carbonyloxy group with 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group with 1 to 8 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbon oxy group with 1 to 8 carbon atoms which may be substituted by a halogen atom. The aforementioned saturated hydrocarbon group, saturated hydrocarbon oxy group, and saturated hydrocarbon carbonyloxy group may be linear, branched, or cyclic. When g is 2 or more, each R 31 may be the same or different from each other. When h is 2 or more, each R32 They may be the same as or different from each other.

[0272] In formula (C3), R B is the same as described above. i is an integer from 0 to 5. j is an integer from 0 to 2.

[0273] In formula (C3), R 33 is an acetyl group, a saturated hydrocarbon group having 1 to 20 carbon atoms, a saturated hydrocarbon oxy group having 1 to 20 carbon atoms, a saturated hydrocarbon carbonyl oxy group having 2 to 20 carbon atoms, a saturated hydrocarbon oxy hydrocarbon group having 2 to 20 carbon atoms, a saturated hydrocarbon thio hydrocarbon group having 2 to 20 carbon atoms, a halogen atom, a nitro group or a cyano group. When j is 1 or 2, it may also be a hydroxyl group. The aforementioned saturated hydrocarbon group, saturated hydrocarbon oxy group, saturated hydrocarbon carbonyl oxy group, saturated hydrocarbon oxy hydrocarbon group and saturated hydrocarbon thio hydrocarbon group may be linear, branched or cyclic. When i is 2 or more, each R 33 They may be the same as or different from each other.

[0274] In formula (C3), Y 4 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is the atomic bond between the carbon atom of the main chain.

[0275] In formula (C3), A 3 is a single bond or a saturated alkylene group having 1 to 10 carbon atoms. A part of -CH2- constituting the saturated alkylene group may also be replaced by -O-. The aforementioned saturated alkylene group may be linear, branched or cyclic. Specific examples thereof may be the same as those exemplified for A 1 in formula (B1).

[0276] When repeating units C1 to C3 are used, in addition to the etching resistance of the aromatic ring, an effect of high EB irradiation resistance during etching and pattern inspection obtained by adding the ring structure to the main chain can be obtained.

[0277] In order to obtain a better effect of etching resistance, it is preferably introduced at 5 mol% or more in all the repeating units of the polymer contained in the base polymer for repeating units C1 to C3. Further, it is preferably introduced at 35 mol% or less, more preferably at 30 mol% or less, in all the repeating units constituting the base polymer for repeating units C1 to C3. When no functional group is present or the functional group is not any of the above, if the introduction amount of repeating units C1 to C3 is 35 mol% or less, there is no fear of developing defects, which is more ideal. Repeating units C1 to C3 may be used alone or in combination of two or more.

[0278] In all the repeating units of the polymer contained in the aforementioned base polymer, the content of at least one selected from repeating unit B1, repeating unit B2, repeating unit B3 and repeating units C1 to C3 is preferably 60 mol% or more, more preferably 70 mol% or more.

[0279] The aforementioned polymer may also contain commonly used (meth)acrylate units protected with acid-labile groups, and (meth)acrylate units having adhesion groups such as a lactone structure and a hydroxyl group other than a phenolic hydroxyl group. The properties of the resist film can be finely adjusted by these repeating units, but these units may also be absent.

[0280] The aforementioned (meth)acrylate units having adhesion groups are, for example, the repeating unit represented by the following formula (C4) (hereinafter also referred to as repeating unit C4), the repeating unit represented by the following formula (C5) (hereinafter also referred to as repeating unit C5), and the repeating unit represented by the following formula (C6) (hereinafter also referred to as repeating unit C6). These units do not exhibit acidity and can be used as units for providing adhesion to the substrate and units for adjusting solubility as auxiliary.

[0281] [Chemical formula 51]

[0282]

[0283] In formulas (C4) to (C6), R B is the same as described above. R 34 is -O- or a methylene group. R 35 is a hydrogen atom or a hydroxyl group. R 36 is a saturated hydrocarbon group having 1 to 4 carbon atoms. k is an integer of 0 to 3.

[0284] When these units are contained, their content is preferably 0 to 30 mol%, more preferably 0 to 20 mol%, based on all the repeating units of the polymer contained in the aforementioned base polymer. The repeating units C4 to C6 can be used alone or in combination of two or more.

[0285] The aforementioned base polymer may also be a mixture of a polymer containing repeating units A1 to A8 and a polymer not containing repeating units A1 to A8. Specifically, it is a polymer containing the repeating unit represented by formula (B1) and at least one selected from the repeating unit represented by formula (B2) and the repeating unit represented by formula (B3), and not containing the repeating units represented by formulas (A1) to (A8). In this case, the content of the polymer not containing repeating units A1 to A8 is preferably 2 to 5,000 parts by mass, more preferably 10 to 1,000 parts by mass, relative to 100 parts by mass of the polymer containing repeating units A1 to A8.

[0286] The aforementioned polymer can be synthesized by a known method by copolymerizing each monomer protected with a protecting group as needed and then performing a deprotection reaction as needed. The copolymerization reaction is not particularly limited, and radical polymerization and anionic polymerization are preferably used. For these methods, reference can be made to Japanese Patent Application Laid-Open No. 2004-115630.

[0287] The weight-average molecular weight (Mw) of the aforementioned polymer is preferably from 1,000 to 50,000, more preferably from 2,000 to 20,000. If Mw is 1,000 or more, there is no fear of the phenomenon that the head of the pattern becomes round as known in the past, the resolution decreases, and at the same time the LER deteriorates. On the other hand, if Mw is 50,000 or less, especially when forming a pattern with a pattern line width of 100 nm or less, there is no fear of LER deterioration. Further, in the present invention, Mw is a polystyrene conversion measurement value obtained by gel permeation chromatography (GPC) using tetrahydrofuran (THF) or dimethylformamide (DMF) as a solvent.

[0288] For the aforementioned polymer, the molecular weight distribution (Mw / Mn) is preferably from 1.0 to 2.0, more preferably from 1.0 to 1.9, and even more preferably from 1.0 to 1.8, with a narrow dispersion being preferred. Thus, in the case of a narrow dispersion, no foreign matter will appear on the pattern after development, and the shape of the pattern will not deteriorate.

[0289] Further, for the design of the aforementioned base polymer, the dissolution rate in an alkali developer is preferably 8 nm / min or less, more preferably 6 nm / min or less, and even more preferably 5 nm / min or less. In the next generation, when the film coated on the substrate is in the thin film region (100 nm or less), the influence on the pattern film loss during alkali development increases. When the alkali dissolution rate of the polymer is greater than 8 nm / min, the pattern will collapse and a fine pattern cannot be formed. Especially when defect-free photomask production is required, the development process has a stronger tendency, so it is more significant. Further, in the present invention, the dissolution rate of the base polymer in an alkali developer is calculated from the film loss amount when a polymer solution (polymer concentration: 16.7% by mass, solvent: propylene glycol monomethyl ether (PGME)) is spin-coated on an 8-inch silicon wafer, baked at 100 °C for 90 seconds to form a film with a film thickness of 1,000 nm, and then developed with a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) at 23 °C for 100 seconds.

[0290] [Polymer containing fluorine atoms]

[0291] In the chemically amplified positive resist composition of the present invention, in order to achieve high contrast, shield the chemical flash of acid during high-energy ray irradiation, and prevent the mixing of acid from the antistatic film material during the treatment of coating the antistatic film on the resist, and suppress unexpected and undesirable pattern deterioration, it may also contain at least one selected from the repeating units represented by the following formula (D3), the repeating units represented by the following formula (D4), the repeating units represented by the following formula (D5), and the repeating units represented by the following formula (D6) (hereinafter each is referred to as repeating units D3, D4, D5, and D6), and may further contain at least one selected from the repeating units represented by the following formula (D1) and the repeating units represented by the following formula (D2) (hereinafter each is referred to as repeating units D1 and D2), a fluorine atom-containing polymer. Since the aforementioned fluorine atom-containing polymer also has the function of a surfactant, it can prevent the reattachment of insoluble substances that may be generated during the development process to the substrate, and can also exert an effect on development defects.

[0292] [Chemical 52]

[0293]

[0294] In formulas (D1) to (D6), R C are each independently a hydrogen atom or a methyl group. R D are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 101 is a hydrogen atom, or a linear or branched hydrocarbon group having 1 to 5 carbon atoms in which a heteroatom-containing group may be inserted between carbon-carbon bonds. R 102 is a linear or branched hydrocarbon group having 1 to 5 carbon atoms in which a heteroatom-containing group may be inserted between carbon-carbon bonds. R 103 is a saturated hydrocarbon group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted by a fluorine atom, and a part of -CH2- constituting the aforementioned saturated hydrocarbon group may be substituted by an ester bond or an ether bond. R 104 、R 105 、R 107 and R 108 are each independently a hydrogen atom or a saturated hydrocarbon group having 1 to 10 carbon atoms. R 106 、R 109 、R 110 and R 111 are each independently a hydrogen atom, a hydrocarbon group having 1 to 15 carbon atoms, a fluorinated hydrocarbon group having 1 to 15 carbon atoms, or an acid-labile group. When R 106 、R 109 、R 110 and R 111 are a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group may be inserted between carbon-carbon bonds. x is an integer of from 1 to 3. y is an integer satisfying 0 ≤ y ≤ 5 + 2z - x. z is 0 or 1. m is an integer of from 1 to 3. Z 1It is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is an atomic bond between the carbon atoms of the main chain. 2 is a single bond, -O-, *-C(=O)-OZ 21 -Z 22 - or *-C(=O)-NH-Z 21 -Z 22 -.Z 21 Z is a single bond or a saturated alkylene group having 1 to 10 carbon atoms. 22 It is a single bond, ester bond, ether bond or sulfonamide bond. *It is an atomic bond between the carbon atoms of the main chain. 3 It is a (m+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (m+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms.

[0295] R 101 and R 102 Examples of the hydrocarbon group having 1 to 5 carbon atoms represented by are alkyl, alkenyl, and alkynyl, with alkyl being preferred. Examples of the aforementioned alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and n-pentyl. Furthermore, groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms may be inserted between the carbon-carbon bonds of these groups.

[0296] In formula (D1), -OR 101 In this case, R 101 Preferred are hydrogen atoms, alkyl groups having 1 to 5 carbon atoms with oxygen atoms inserted between carbon-carbon bonds, and the like.

[0297] The repeating unit D1 can be listed below but is not limited to these. In the following formula, R C Same as above.

[0298] [Chemistry 53]

[0299]

[0300] [Chemistry 54]

[0301]

[0302] Z 1 It is preferably *-C(=O)-O- or *-C(=O)-NH-. C Preferably, Z is methyl. 1 The presence of carbonyl groups improves the ability to capture acid from the antistatic film. C Methyl groups form a rigid polymer with a higher glass transition temperature (Tg), thereby suppressing acid diffusion, thereby improving the stability of the resist film over time and preventing degradation of resolution and pattern shape.

[0303] Z 21The saturated alkylene group having 1 to 10 carbon atoms may be linear, branched or cyclic. Specific examples thereof include methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-1,3-diyl, propane-2,2-diyl, butane-1,1-diyl, butane-1,2-diyl, butane-1,3-diyl, butane-2,3-diyl, butane-1,4-diyl, and 1,1-dimethylethane-1,2-diyl.

[0304] R 103 The saturated hydrocarbon group having 1 to 20 carbon atoms in which at least one hydrogen atom is replaced by a fluorine atom may be linear, branched or cyclic. Specific examples thereof are given in the description of formulas (A1) to (A8). 1 ~R 18 The hydrocarbon group represented by is an alkyl group or a cyclic saturated hydrocarbon group exemplified by substituted with a fluorine atom.

[0305] The repeating unit D2 can be listed below but is not limited to these. In the following formula, R C Same as above.

[0306] [Chemistry 55]

[0307]

[0308] [Chemistry 56]

[0309]

[0310] [Chemistry 57]

[0311]

[0312] [Chemistry 58]

[0313]

[0314] R 104 、R 105 、R 107 and R 108 Examples of the saturated hydrocarbon group having 1 to 10 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; and cyclic saturated hydrocarbon groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornyl. Among these, saturated hydrocarbon groups having 1 to 6 carbon atoms are preferred.

[0315] R 106 、R 109 、R 110 and R 111Examples of the hydrocarbon group having 1 to 15 carbon atoms represented include alkyl groups, alkenyl groups, alkynyl groups, etc., with alkyl groups being preferred. In addition to those described above, examples of the alkyl group include n-undecyl, n-dodecyl, tridecyl, tetradecyl, pentadecyl, etc. Further, examples of the fluorinated hydrocarbon group include groups in which a part or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbon group are substituted with fluorine atoms.

[0316] Z 3 Examples of the (m + 1)-valent hydrocarbon group having 1 to 20 carbon atoms and the (m + 1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented include groups obtained by removing m hydrogen atoms from the aforementioned hydrocarbon group or fluorinated hydrocarbon group, etc.

[0317] Specific examples of the repeating units D3 to D6 are listed below, but are not limited to these. Further, in the following formula, R D Same as the above.

[0318] [Chemical formula 59]

[0319]

[0320] [Chemical formula 60]

[0321]

[0322] [Chemical formula 61]

[0323]

[0324] The content of the repeating unit D1 and / or D2 is preferably 5 to 85 mol% in all the repeating units of the aforementioned fluorine atom-containing polymer, and more preferably 15 to 80 mol%. The content of the repeating units D3 to D6 is preferably 15 to 95 mol% in all the repeating units of the aforementioned fluorine atom-containing polymer, and more preferably 20 to 85 mol%. The repeating units D1 to D6 can be used alone or in combination of two or more.

[0325] The aforementioned fluorine atom-containing polymer may also contain other repeating units in addition to the aforementioned repeating units. Examples of such repeating units include those described in paragraphs

[0046] to

[0078] of Japanese Unexamined Patent Application Publication No. 2014-177407. When (D) the fluorine atom-containing polymer contains other repeating units, the content is preferably 50 mol% or less in all the repeating units of the aforementioned fluorine atom-containing polymer.

[0326] The aforementioned fluorine atom-containing polymer can be synthesized by copolymerizing each monomer, which may be protected by a protecting group as needed, by a known method, and then performing a deprotection reaction as needed. The copolymerization reaction is not particularly limited, and radical polymerization and anionic polymerization are preferred. These methods can be referred to Japanese Unexamined Patent Application Publication No. 2004-115630.

[0327] The Mw of the aforementioned fluorine atom-containing polymer is preferably from 2,000 to 50,000, more preferably from 3,000 to 20,000. If the Mw is less than 2,000, acid diffusion is promoted, and sometimes the resolution deteriorates and the stability over time is impaired. If the Mw is too large, the solubility in the solvent decreases, and sometimes coating defects occur. Further, the Mw / Mn of the aforementioned fluorine atom-containing polymer is preferably from 1.0 to 2.2, more preferably from 1.0 to 1.7.

[0328] When the chemically amplified positive resist composition of the present invention contains the aforementioned fluorine atom-containing polymer, the content thereof is preferably from 0.01 to 30 parts by mass, more preferably from 0.1 to 20 parts by mass, still more preferably from 0.5 to 10 parts by mass, based on 80 parts by mass of the base polymer.

[0329] [Organic solvent]

[0330] The chemically amplified positive resist composition of the present invention may also contain an organic solvent. There is no particular limitation on the aforementioned organic solvent as long as each component is soluble. Such organic solvents include, for example, ketones such as cyclohexanone and methyl-2-n-amyl ketone described in paragraphs

[0144] to

[0145] of JP-A-2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; ethers such as PGME, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, ethyl lactate (EL), ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monoter-butyl ether acetate; lactones such as γ-butyrolactone; and mixed solvents thereof. When an acetal-based acid-labile group is used, in order to accelerate the deprotection reaction of the acetal, a high-boiling alcohol-based solvent may be added. Specifically, diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, 1,3-butanediol, etc. may be added.

[0331] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, PGME, cyclohexanone, EL, γ-butyrolactone, and mixed solvents thereof are preferred.

[0332] When the chemically amplified positive resist composition of the present invention contains the aforementioned organic solvent, the content thereof is preferably from 200 to 10,000 parts by mass, more preferably from 400 to 5,000 parts by mass, based on 80 parts by mass of the base polymer. The organic solvent may be used alone or in combination of two or more.

[0333] [Photoacid generator]

[0334] The chemically amplified positive resist composition of the present invention may also contain a photoacid generator (hereinafter also referred to as an additive photoacid generator). The photoacid generator is not particularly limited as long as it is a compound that generates an acid upon irradiation with high-energy rays. Ideal photoacid generators include sulfonium salts, iodonium salts, sulfonyl diazomethanes, N-sulfonyloxyimides, oxime-O-sulfonate type acid generators, and the like.

[0335] Specific examples of the photoacid generator include nonafluorobutanesulfonate, partially fluorinated sulfonates described in paragraphs

[0247] to

[0251] of JP-A-2012-189977, partially fluorinated sulfonates described in paragraphs

[0261] to

[0265] of JP-A-2013-101271, those described in paragraphs

[0122] to

[0142] of JP-A-2008-111103, those described in paragraphs

[0080] to

[0081] of JP-A-2010-215608, and the like. Among these specific examples, arylsulfonate type or alkylsulfonate type photoacid generators generate an acid of moderate strength for deprotecting the acid-labile group of the repeating unit represented by formula (B2) or (B3), and thus are ideal.

[0336] Such a photoacid generator is preferably a compound having a sulfonium anion with the structure shown below. Specific examples of the paired cations are those described above for the sulfonium cations in formulas (A2) to (A4).

[0337] [Chemical formula 62]

[0338]

[0339] [Chemical formula 63]

[0340]

[0341] [Chemical formula 64]

[0342]

[0343] [Chemical formula 65]

[0344]

[0345] [Chemical formula 66]

[0346]

[0347] [Chemical formula 67]

[0348]

[0349] [Chemical formula 68]

[0350]

[0351] The acid generated by the aforementioned photoacid generator preferably has a pKa of -2.0 or higher. Also, the upper limit of the pKa is preferably 2.0. The pKa value is calculated using the pKa DB of the software ACD / Chemsketch ver: 9.04 manufactured by Advanced Chemistry Development, Inc.

[0352] When the chemically amplified positive resist composition of the present invention contains an additive photoacid generator, its content is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, relative to 80 parts by mass of the aforementioned base polymer. The aforementioned additive photoacid generator can be used alone or in combination of two or more.

[0353] [Quencher]

[0354] The chemically amplified positive resist composition of the present invention preferably contains a quencher. Examples of the aforementioned quencher include known types of basic compounds. Examples of known types of basic compounds include primary, secondary, and tertiary aliphatic amines, hybrid amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, urethanes, etc. In particular, the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Application Laid-Open No. 2008-111103, especially amine compounds having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group, a sulfonate bond, or the compounds having a urethane group described in Japanese Patent No. 3790649 are preferred. Preferred examples include tris[2-(methoxymethoxy)ethyl]amine, tris[2-(methoxymethoxy)ethyl]amine N-oxide, dibutylaminobenzoic acid, morpholine derivatives, imidazole derivatives, etc. By adding such a basic compound, for example, the diffusion rate of the acid in the resist film can be further suppressed, or the shape can be corrected.

[0355] Also, examples of the aforementioned quencher include sulfonium salts, iodonium salts, ammonium salts, etc. of α-position unfluorinated carboxylic acids described in Japanese Patent Application Laid-Open No. 2008-158339. Sulfonic acids, imidic acids, or methylated acids fluorinated at the α-position are necessary for deprotecting acid-labile groups, but α-position unfluorinated carboxylic acids are released by salt exchange with α-position unfluorinated iodonium salts. α-position unfluorinated carboxylic acids hardly cause deprotection reactions, so they act as quenchers.

[0356] The iodonium salt of α-position unfluorinated carboxylic acid is represented by, for example, the following formula (F1).

[0357] [Chemical formula 69]

[0358]

[0359] In formula (F1), R 201 is a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms which may also contain a heteroatom, provided that the hydrogen atom bonded to the carbon atom at the α-position of the carboxyl group is not substituted with a fluorine atom or a fluoroalkyl group.

[0360] The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 40 carbon atoms such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, etc.; cycloaliphatic saturated hydrocarbon groups having 3 to 40 carbon atoms such as cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, tricyclo[5.2.1.0 2,6 decyl, adamantyl, adamantylmethyl, etc.; alkenyl groups having 2 to 40 carbon atoms such as vinyl, allyl, propenyl, butenyl, hexenyl, etc.; cycloaliphatic unsaturated aliphatic hydrocarbon groups having 3 to 40 carbon atoms such as cyclohexenyl, etc.; aryl groups having 6 to 40 carbon atoms such as phenyl, naphthyl, alkylphenyl (2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, 4-n-butylphenyl, etc.), dialkylphenyl (2,4-dimethylphenyl, 2,4,6-triisopropylphenyl, etc.), alkylnaphthyl (methylnaphthyl, ethylnaphthyl, etc.), dialkylnaphthyl (dimethylnaphthyl, diethylnaphthyl, etc.), etc.; aralkyl groups having 7 to 40 carbon atoms such as benzyl, 1-phenylethyl, 2-phenylethyl, etc.

[0361] Furthermore, a part of the hydrogen atoms of these groups may also be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and a part of the carbon atoms of these groups may also be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc., and as a result, it may also contain hydroxyl groups, cyano groups, carbonyl groups, ether bonds, thioether bonds, ester bonds, sulfonate ester bonds, carbonate ester bonds, lactone rings, sultone rings, carboxylic anhydrides, haloalkyl groups, etc. Examples of the hydrocarbon group containing a heteroatom include: heteroaryl groups such as thienyl; alkoxyphenyl groups such as 4-hydroxyphenyl, 4-methoxyphenyl, 3-methoxyphenyl, 2-methoxyphenyl, 4-ethoxyphenyl, 4-tert-butoxyphenyl, 3-tert-butoxyphenyl, etc.; alkoxynaphthyl groups such as methoxynaphthyl, ethoxynaphthyl, n-propoxynaphthyl, n-butoxynaphthyl, etc.; dialkoxynaphthyl groups such as dimethoxynaphthyl, diethoxynaphthyl, etc.; aryl oxoalkyl groups such as 2-aryl-2-oxoethyl groups such as 2-phenyl-2-oxoethyl, 2-(1-naphthyl)-2-oxoethyl, 2-(2-naphthyl)-2-oxoethyl, etc.

[0362] In formula (F1), Mq +is an onium cation. It is preferable that the onium cation is a sulfonium cation, an iodonium cation or an ammonium cation, and more preferably a sulfonium cation or an iodonium cation. Examples of the sulfonium cation include the same as those exemplified for the sulfonium cation in formulas (A2) to (A4). Examples of the iodonium cation include the same as those exemplified for the iodonium cation in formulas (A5) to (A8).

[0363] Examples of the anion of the salt represented by formula (F1) include, but are not limited to, the following.

[0364] [Chemical formula 70]

[0365]

[0366] [Chemical formula 71]

[0367]

[0368] [Chemical formula 72]

[0369]

[0370] The aforementioned quencher is also preferably a sulfonium salt of a benzenecarboxylic acid containing an iodobenzene ring represented by the following formula (F2).

[0371] [Chemical formula 73]

[0372]

[0373] In formula (F2), R 301 is a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or a saturated hydrocarbon group having 1 to 6 carbon atoms, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms, or a saturated hydrocarbon sulfonyloxy group having 1 to 4 carbon atoms, in which part or all of the hydrogen atoms may be substituted by halogen atoms, or -N(R 301A )-C(=O)-R 301B or -N(R 301A )-C(=O)-O-R 301B . R 301A is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. R 301B is a saturated hydrocarbon group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbon group having 2 to 8 carbon atoms.

[0374] In formula (F2), x is an integer from 1 to 5. y is an integer from 0 to 3. z is an integer from 1 to 3. L 1 is a single bond or a (z + 1)-valent linking group having 1 to 20 carbon atoms, and may contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate group, a halogen atom, a hydroxyl group, and a carboxyl group. The aforementioned saturated hydrocarbon group, saturated hydrocarbon oxy group, saturated hydrocarbon carbonyloxy group, and saturated hydrocarbon sulfonyloxy group may be linear, branched, or cyclic. When y and / or z is 2 or more, each R301 They may be the same as or different from each other.

[0375] In formula (F2), R 302 , R 303 and R 304 are each independently a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, etc. Further, part or all of the hydrogen atoms of these groups may also be substituted with a hydroxyl group, a carboxyl group, a halogen atom, an oxo group, a cyano group, a nitro group, a sultone group, a sulfone group or a group containing a sulfonium salt, and part of the carbon atoms of these groups may also be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate group or a sulfonate bond. Further, R 302 and R 303 may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded.

[0376] Specific examples of the compound represented by formula (F2) include those described in JP-A-2017-219836. The compound represented by formula (F2) has high absorption and high sensitizing effect, and also has high acid diffusion control effect.

[0377] As the aforementioned quencher, a carboxylate compound containing a nitrogen atom represented by the following formula (F3) can be used.

[0378] [Chemical formula 74]

[0379]

[0380] In formula (F3), R 401 to R 404 are each independently a hydrogen atom, -L 2 -CO2 - , or a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom. R 401 and R 402 , R 402 and R 403 , or R 403 and R 404 may also be bonded to each other and form a ring together with the carbon atom to which they are bonded. L 2 is a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom. R 405 is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom.

[0381] In formula (F3), ring R is a ring having 2 to 6 carbon atoms containing the carbon atoms and nitrogen atoms in the formula, and part or all of the hydrogen atoms bonded to the carbon atoms of the ring may also be a hydrocarbon group having 1 to 20 carbon atoms, or -L 2-CO2 - is substituted, and a part of the carbon atoms of the ring may also be substituted with a sulfur atom, an oxygen atom or a nitrogen atom. The aforementioned ring may be an alicyclic ring or an aromatic ring, and a 5-membered ring or a 6-membered ring is preferred. Specific examples thereof include a pyridine ring, a pyrrole ring, a pyrrolidine ring, a piperidine ring, a pyrazole ring, an imidazoline ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, an imidazoline ring, an oxazole ring, a thiazole ring, a morpholine ring, a thiazine ring, a triazole ring, etc.

[0382] The carboxonium salt represented by formula (F3) has at least one -L 2 -CO2 - group. That is, at least one of R 401 ~R 404 is substituted with -L 2 -CO2 - , and / or at least one of the hydrogen atoms bonded to the carbon atoms of the ring R is substituted with -L 2 -CO2 - .

[0383] In formula (F3), Q + is a sulfonium cation, an iodonium cation or an ammonium cation, but a sulfonium cation is preferred. The aforementioned sulfonium cation can be exemplified by the same ones as those exemplified for the cations in formulas (A2) to (A4).

[0384] The anions of the compounds represented by formula (F3) are exemplified below but are not limited thereto.

[0385] [Chemical formula 75]

[0386]

[0387] [Chemical formula 76]

[0388]

[0389] [Chemical formula 77]

[0390]

[0391] [Chemical formula 78]

[0392]

[0393] [Chemical formula 79]

[0394]

[0395] [Chemical formula 80]

[0396]

[0397] In addition, a betaine-type compound of a weak acid can also be used as the aforementioned quencher. Specific examples thereof are exemplified below but are not limited thereto.

[0398] [Chemical formula 81]

[0399]

[0400] The aforementioned quencher may further include the polymer-type quencher described in Japanese Patent Application Laid-Open No. 2008-239918. By aligning on the surface of the resist film, it improves the rectangularity of the resist pattern. The polymer-type quencher also has the effects of preventing pattern film loss and rounding of the pattern top when using a protective film for immersion exposure.

[0401] When the chemically amplified positive resist composition of the present invention contains a quencher, its content is preferably 0 to 50 parts by mass, more preferably 0.1 to 40 parts by mass, relative to 80 parts by mass of the base polymer. The aforementioned quencher may be used alone or in combination of two or more.

[0402] [Surfactant]

[0403] In the chemically amplified positive resist composition of the present invention, in order to improve the coatability on the substrate, a conventional surfactant may also be contained. When using a surfactant, many examples are described in Japanese Patent Application Laid-Open No. 2004-115630, and most of them are well-known. They can be referred to for selection. The content of the aforementioned surfactant is preferably 0 to 5 parts by mass relative to 80 parts by mass of the aforementioned base polymer. Also, when the aforementioned fluorine atom-containing polymer is contained in the chemically amplified positive resist composition of the present invention, the aforementioned fluorine atom-containing polymer also acts as a surfactant, so the aforementioned surfactant may not be contained.

[0404] Regarding the design of the chemically amplified positive resist composition of the present invention, from the perspective of improving the development load, the dissolution rate of the obtained resist film in the overexposed area in the alkaline developer is preferably 50 nm / sec or more, more preferably 70 nm / sec or more. By being 50 nm / sec or more, even if there are differences in the pattern configuration in the dense and sparse patterns, it can be uniformly dissolved in the alkaline developer, and the line width variation can be reduced. Also, in the present invention, the dissolution rate in the overexposed area is obtained by spin-coating the chemically amplified positive resist composition of the present invention on an 8-inch silicon wafer, baking at 110°C for 60 seconds to form a resist film with a film thickness of 90 nm, exposing with KrF excimer laser using the energy at the end of the deprotection reaction of the polymer, baking at 110°C for 60 seconds, and then using a resist development analyzer to calculate from the film loss amount when developing with a 2.38 mass% TMAH aqueous solution at 23°C.

[0405] Further, for the resist film obtained from the chemically amplified positive resist composition of the present invention, the dissolution rate of the unexposed portion in an alkaline developer is preferably 10 nm / min or less, more preferably 8 nm / min or less, and even more preferably 6 nm / min or less. When the resist film is in the thin film region (100 nm or less), the influence on the pattern film loss in the alkaline developer increases. When the dissolution rate of the unexposed portion is greater than 10 nm / min, the pattern collapses and a fine pattern cannot be formed. Especially when defect-free photomasks are required, the development process has a strong tendency, so it is significant. Further, the dissolution rate of the unexposed portion is calculated from the film loss amount when developing a resist film with a thickness of 80 nm formed by spin-coating the chemically amplified positive resist composition of the present invention on a 6-inch silicon wafer and baking it at 110°C for 240 seconds with an aqueous 2.38% by mass TMAH solution at 23°C for 80 seconds.

[0406] [Resist Pattern Formation Method]

[0407] The resist pattern formation method of the present invention includes the following steps: forming a resist film on a substrate using the aforementioned chemically amplified positive resist composition, irradiating a pattern on the aforementioned resist film using high-energy rays (i.e., exposing the aforementioned resist film using high-energy rays), and developing the irradiated-pattern resist film using an alkaline developer.

[0408] As the aforementioned substrate, for example, substrates for integrated circuit manufacturing (Si, SiO, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflection films, etc.) or substrates for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, Si, SiO, SiO2, SiON, SiONC, CoTa, NiTa, TaBN, SnO2, etc.) can be used. By coating the aforementioned chemically amplified positive resist composition on the aforementioned substrate by spin-coating or other methods to make the film thickness 0.03 - 2 μm, and pre-baking it on a hot plate, preferably at 60 - 150°C for 1 - 20 minutes, more preferably at 80 - 140°C for 1 - 10 minutes, a resist film is formed.

[0409] Then, the aforementioned resist film is exposed using high-energy rays and a pattern is irradiated. Examples of the aforementioned high-energy rays include ultraviolet rays, far ultraviolet rays, excimer lasers (KrF, ArF, etc.), EUV, X-rays, γ-rays, synchrotron radiation, EB, etc. It is preferable to use EUV or EB for exposure in the present invention.

[0410] When using ultraviolet rays, far ultraviolet rays, excimer lasers, EUV, X-rays, γ-rays, or synchrotron radiation as the aforementioned high-energy rays, a mask for forming a target pattern is used for irradiation so that the exposure dose is preferably 1 - 500 mJ / cm 2, more preferably 10 to 400 mJ / cm 2 . When using EB, in order to form the target pattern, direct irradiation is performed so that the exposure amount is preferably 1 to 500 μC / cm 2 , more preferably 10 to 400 μC / cm 2 .

[0411] In addition to the usual exposure method, depending on the situation, an immersion method in which the mask and the resist are infiltrated may also be used. At this time, a water-insoluble protective film may also be used.

[0412] Then, post-exposure baking (PEB) is preferably carried out on a hot plate at 60 to 150 °C for 1 to 20 minutes, more preferably at 80 to 140 °C for 1 to 10 minutes.

[0413] Thereafter, a developer of an alkaline aqueous solution such as TMAH at 0.1 to 5% by mass, preferably 2 to 3% by mass, is used, and development is preferably carried out according to a conventional method such as a dip method, a puddle method, or a spray method under the conditions of 0.1 to 3 minutes, more preferably 0.5 to 2 minutes, to form a target pattern on the substrate.

[0414] Furthermore, the chemically amplified positive resist composition of the present invention is particularly useful because it has good resolution and can form a pattern with small LER. In addition, the chemically amplified positive resist composition of the present invention is particularly useful for forming a pattern on a substrate whose surface has a material that is likely to cause pattern peeling or pattern collapse due to difficulty in obtaining adhesion to the resist pattern. Such substrates include substrates having a metal chromium sputter-deposited on the outermost surface and a chromium compound containing one or more light elements selected from oxygen, nitrogen, and carbon, and substrates having SiO, SiO x , tantalum compounds, molybdenum compounds, cobalt compounds, nickel compounds, tungsten compounds, tin compounds, etc. on the outermost layer. The chemically amplified positive resist composition of the present invention is particularly useful for forming a pattern on a substrate using a blank photomask. At this time, the blank photomask can be a transmission type or a reflection type.

[0415] According to the resist pattern forming method of the present invention, even when using a substrate (for example, a blank photomask) whose outermost surface is made of a material such as a material containing chromium, silicon, or tantalum that is likely to affect the shape of the resist pattern, a pattern with high resolution and suppressed influence of development load and independent of pattern density and small size difference can be obtained.

[0416] [Examples]

[0417] The following are synthesis examples, examples, and comparative examples for specific description of the present invention, but the present invention is not limited to the following examples. The copolymerization composition ratio is a molar ratio, and Mw is the polystyrene-reduced weight average molecular weight measured by GPC.

[0418] [1] Synthesis of sulfonium salt

[0419] [Synthesis Example 1] Synthesis of sulfonium salt PM-1

[0420] [Chemical Formula 82]

[0421]

[0422] According to the method described in Japanese Patent Laid-Open No. 2010-215608, sodium 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropane-1-sulfonate was synthesized. 200 g of dichloromethane and 20.4 g of benzyltrimethylammonium chloride were added to 132 g of an aqueous solution containing the obtained sodium 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropane-1-sulfonate (equivalent to 0.1 mol of sodium 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropane-1-sulfonate), and the mixture was stirred for 30 minutes. Liquid separation, extraction, and washing with water of the stirred aqueous solution were carried out, and then the organic layer was concentrated, methyl isobutyl ketone was added, and concentration was carried out again. Diisopropyl ether was added to the concentrated solution for recrystallization, and the precipitated solid was recovered and dried under reduced pressure to obtain the benzyltrimethylammonium salt.

[0423] 15.0 g of triethylamine and 200 g of dichloromethane were added to the obtained benzyltrimethylammonium salt. 11.5 g of methacryloyl chloride was added to this mixed solution under ice cooling, and after stirring overnight at room temperature, 100 g of water was added to the reaction solution to stop the reaction. The quenched reaction solution was separated, and an aqueous solution of triphenylsulfonium chloride was added to the extracted organic layer, followed by stirring for 30 minutes, liquid separation, and washing with water. Then the organic layer was concentrated, methyl isobutyl ketone was added, and concentration was carried out again. Diisopropyl ether was added to the concentrated solution for recrystallization, and the precipitated solid was recovered and dried under reduced pressure to obtain a white solid of triphenylsulfonium 2-(methacryloyloxy)-3,3,3-trifluoro-2-trifluoromethylpropane-1-sulfonate (PM-1) (yield 85%).

[0424] [2] Synthesis of polymer

[0425] [Synthesis Example 2-1] Synthesis of polymer P-1

[0426] Under a nitrogen atmosphere, 25.5 g of a 50.0 mass% PGMEA solution of 4-hydroxystyrene, 9.3 g of ethylcyclopentyl methacrylate, 12.7 g of 1-(1-methylcyclopentyloxy)-4-vinylbenzene, 17.5 g of PM-1, 4.1 g of dimethyl 2,2'-azobis(2-methylpropionate) (manufactured by Fuji Photo Film Co., Ltd., trade name V-601), 24 g of γ-butyrolactone as a solvent, and 30 g of PGMEA were added to a 200 mL dropping cylinder to prepare a solution.

[0427] In another 300 mL polymerization flask under a nitrogen atmosphere, 40 g of γ-butyrolactone was added. While maintaining the temperature at 80°C, the previously prepared solution was added dropwise over 4 hours. After the addition was completed, the mixture was stirred at 80°C for 18 hours and then cooled to room temperature.

[0428] The obtained polymerization solution was added dropwise to 400 g of diisopropyl ether, and a solid precipitated. The solution with the precipitated solid was allowed to stand, and the diisopropyl ether was removed by decantation. The precipitated solid was dissolved in 100 g of acetone. This acetone solution was added dropwise to 400 g of diisopropyl ether, and the precipitated solid was separated by filtration. The solid separated by filtration was dissolved again in 100 g of acetone, and this acetone solution was added dropwise to 400 g of water, and the precipitated solid was separated by filtration. Thereafter, the solid separated by filtration was dried at 40°C for 40 hours to obtain 35 g of a white solid polymer P-1. The obtained polymer P-1 was 1 analyzed by 1H-NMR, 13 13C-NMR, and GPC, and the results were the following analysis results.

[0429] [Chemical formula 83]

[0430]

[0431] [Synthesis Examples 2-2 to 2-58, Comparative Synthesis Examples 1-1 to 1-2] Polymers P-2 to P-58, Comparative Polymers cP-1 to cP-2

[0432] By changing the types and blending ratios of the respective monomers, the polymers P-2 to P-58 and comparative polymers cP-1 to cP-2 shown in the following Tables 1 to 3 were synthesized in the same manner as in Synthesis Example 2-1. Also, in the following Tables 1 to 3, the introduction ratio represents the molar ratio.

[0433] [Table 1]

[0434]

[0435] [Table 2]

[0436]

[0437] [Table 3]

[0438]

[0439] Also, the structure of the repeating unit introduced into the polymer is as follows.

[0440] [Chemical formula 84]

[0441]

[0442] [Chemical formula 85]

[0443]

[0444] [Chemistry 86]

[0445]

[0446] [Chemistry 87]

[0447]

[0448] [Chemistry 88]

[0449]

[0450] [Chemistry 89]

[0451]

[0452] The dissolution rate of the aforementioned polymers in an alkaline developer was determined by spin-coating a polymer solution (polymer concentration: 16.7% by mass, solvent: PGME) onto an 8-inch silicon wafer, baking it at 100°C for 90 seconds to form a 1,000 nm thick film. The film was then developed with a 2.38% by mass TMAH aqueous solution at 23°C for 100 seconds, and the film loss was measured and calculated. The results showed that the dissolution rates of polymers P-1 to P-58 and comparative polymers cP-1 and cP-2 were 5 nm / min or less.

[0453] [Synthesis Examples 3-1 to 3-8] Synthesis of Polymers AP-1 to AP-11

[0454] Polymers AP-1 to AP-11 were synthesized in the same manner as in Synthesis Example 2-1 except that the raw material compounds used were changed.

[0455] [Chemistry 90]

[0456]

[0457] [Chemistry 91]

[0458]

[0459] [Chemistry 92]

[0460]

[0461] The dissolution rates of polymers AP-1 to AP-11 were 5 nm / min or less.

[0462] [3] Preparation of chemically amplified positive resist compositions

[0463] [Examples 1-1 to 1-90, Comparative Examples 1-1 to 1-4]

[0464] Dissolve each component in an organic solvent according to the composition shown in Tables 4 to 8 below, and filter the obtained solution through a UPE filter with a size of 0.02 μm to prepare a chemically amplified positive resist composition.

[0465] Furthermore, the aforementioned organic solvent is a mixed solvent of 340 parts by mass of PGMEA, 1,700 parts by mass of EL, and 1,360 parts by mass of PGME. Furthermore, 0.075 parts by mass of FC-4430 (manufactured by 3M Company), which is a surfactant, is added to the aforementioned organic solvent.

[0466] [Table 4]

[0467]

[0468]

[0469] [Table 5]

[0470]

[0471]

[0472] [Table 6]

[0473]

[0474]

[0475] [Table 7]

[0476]

[0477] [Table 8]

[0478]

[0479] Furthermore, in Tables 4 to 8, the structures of the quenching agents Q-1 to Q-3, the photoacid generators PAG-A to PAG-C, and the polymers D-1 to D-5 are as shown below.

[0480] [Chemical Formula 93]

[0481]

[0482] [Chemical Formula 94]

[0483]

[0484] [Chemical Formula 95]

[0485]

[0486] [4] EB Lithography Evaluation

[0487] [Examples 2-1 to 2-90, Comparative Examples 2-1 to 2-3]

[0488] Each chemically amplified positive resist composition (R-1 to R-90, CR-1 to CR-3) was spin-coated onto a blank photomask with a chromium top surface of 152 mm square using ACT-M (manufactured by Tokyo Electron Limited), prebaked on a hot plate at 110 °C for 600 seconds, and a resist film with a thickness of 80 nm was formed. The thickness of the obtained resist film was measured using an optical measuring instrument NANOSPEC (manufactured by NANOMETRICS). The measurement was performed at 81 points in the plane of the blank substrate except for the outer edge portion from the outer circumference to 10 mm inside, and the average film thickness and the film thickness range were calculated.

[0489] Also, exposure was performed using an electron beam exposure apparatus (EBM-5000plus manufactured by Nuflare Technology, acceleration voltage 50 kV), PEB was performed at 110 °C for 600 seconds, and development was performed with a 2.38 mass% TMAH aqueous solution to obtain a positive pattern.

[0490] The obtained resist pattern was evaluated as follows. The blank mask with the pattern was observed by top-down SEM (scanning electron microscope), and the exposure dose at which a 1:1 line and space (LS) of 200 nm was resolved at 1:1 was defined as the optimum exposure dose (μC / cm 2 ), the minimum dimension in the exposure dose at which a 200 nm LS was resolved at 1:1 was defined as the resolution (limiting resolution), and the line edge roughness (LER) of the 200 nm LS was measured by SEM. For the evaluation of development loading, the exposure dose (μC / cm 2 ) at which a 200 nm LS pattern designed in the plane of the substrate at a 1:1 ratio of 1:1 line and space (LS) was resolved, and the pitch dimensions of the 200 nm LS patterns with virtual patterns having densities of 15%, 25%, 33%, 45%, 50%, 55%, 66%, 75%, and 85% each arranged around this pattern were compared to compare the size differences between the dense and sparse patterns. For the pattern shape, it was visually determined whether it was rectangular.

[0491] The dissolution rate of the overexposed portion was calculated by spin-coating a resist solution onto an 8-inch silicon wafer, baking at 110 °C for 60 seconds to form a resist film with a thickness of 90 nm, exposing with a KrF excimer laser at the exposure dose (mJ / cm 2 ) at which a 1:1 line and space (LS) of 200 nm was resolved at 1:1, baking at 110 °C for 60 seconds, and then developing with a 2.38 mass% TMAH aqueous solution at 23 °C using a resist development analyzer (RDA-8 manufactured by LITHO TECH JAPAN). The results are shown in Tables 9 to 12.

[0492] [Table 9]

[0493]

[0494] [Table 10]

[0495]

[0496] [Table 11]

[0497]

[0498] [Table 12]

[0499]

[0500] The chemically amplified positive resist compositions (R-1 to R-90) of the present invention all exhibited good resolution, LER, and pattern rectangularity, and showed values with suppressed development load. On the other hand, the comparative resist compositions (CR-1 to CR-3) exhibited insufficient development load suppression due to the excessively slow dissolution rate of the overexposed portion of CR-1. While CR-2 and CR-3 exhibited good development load, they failed to achieve a balance between resolution, LER, and pattern rectangularity due to the suboptimal design of their base polymers. This is believed to be due to the design of the base polymer, specifically, the acid diffusion suppression effect achieved by forming a PAG-bound polymer backbone. Furthermore, by combining phenolic acid-labile groups with acrylate acid-labile groups, the phenolic units successfully optimized the pattern shape and the acrylate-based acid-labile groups, achieving resolution, LER, pattern rectangularity, and suppressed development load. The resist pattern formation method using the chemically amplified positive resist composition of the present invention is useful in optical lithography for semiconductor device manufacturing, particularly in the processing of transmissive and reflective photomask blanks.

Claims

1. A chemically amplified positive resist composition containing a base polymer protected by acid-labile groups and becoming alkali-soluble by the action of acid, The base polymer comprises: a polymer containing an acid-generating unit, a unit having a phenolic hydroxyl group, a unit in which the phenolic hydroxyl group is protected by an acid-labile group, and a unit in which a carboxyl group is protected by an acid-labile group, or comprising: a polymer containing an acid-generating unit, a unit having a phenolic hydroxyl group, and a unit in which the phenolic hydroxyl group is protected by an acid-labile group, and a polymer containing an acid-generating unit, a unit having a phenolic hydroxyl group, and a unit in which a carboxyl group is protected by an acid-labile group; the acid-generating unit is a repeating unit represented by any one of the following formulas (A1) to (A8), the unit having a phenolic hydroxyl group is a repeating unit represented by the following formula (B1), the unit in which the phenolic hydroxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (B2), the unit in which the carboxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (B3), in all the repeating units of the polymer contained in the base polymer, the repeating units having an aromatic ring skeleton are 60 mol% or more; In the formula, R A each independently represents a hydrogen atom or a methyl group; X 1 is a single bond, an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining them, or *-O-X 11 -, *-C(=O)-O-X 11 -, or *-C(=O)-NH-X 11 -, X 11 is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining them, and may also contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group; X 2 is a single bond or **-X 21 -C(=O)-O-, X 21 is an alkylene group having 1 to 20 carbon atoms which may also contain heteroatoms; X 3 is a single bond, methylene, ethylene, phenylene, fluorophenylene, phenyl substituted with trifluoromethyl, *-O-X 31 -, *-C(=O)-O-X 31 - or *-C(=O)-NH-X 31 -, X 31 is an aliphatic alkylene group having 1 to 6 carbon atoms, phenylene, fluorophenylene, phenyl substituted with trifluoromethyl, or a group having 7 to 20 carbon atoms obtained by combining them, and may also contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group; * is an atomic bond between the carbon atom of the main chain, and ** is an atomic bond between the oxygen atom in the formula; X 4 is a single bond or an alkylene group having 1 to 30 carbon atoms which may also contain a heteroatom; k 1 and k 2 are each independently 0 or 1, provided that when X 4 is a single bond, k 1 and k 2 are 0; R 1 ~R 18 Each independently represents a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom; further, R 1 and R 2 may also be bonded to each other and together with the sulfur atom to which they are bonded form a ring, R 3 and R 4 、R 6 and R 7 、or R 9 and R 10 may also be bonded to each other and together with the sulfur atoms to which they are bonded form a ring, R HF is a hydrogen atom or a trifluoromethyl group; Xa - is a non-nucleophilic relative ion; In the formula, R B is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, R 21 is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbon oxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom. Y 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, where * is a bond between an atom and a carbon atom of the main chain; A 1 is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a part of -CH2- constituting the saturated alkylene group may also be substituted by -O-; a is an integer satisfying 0 ≤ a ≤ 5 + 2c - b; b is an integer of 1 to 3, c is an integer of 0 to 2, wherein, R B as described above R 22 is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbon oxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom, Y 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, where * is a bond between an atom and a carbon atom of the main chain A 2 is a single bond or a saturated alkylene group with 1 to 10 carbon atoms, and a part of -CH2- constituting the saturated alkylene group may also be substituted by -O-. R 23 is an acid-labile group when e is 1, and is a hydrogen atom or an acid-labile group when e is 2 or more, provided that at least one of them is an acid-labile group; d is an integer satisfying 0 ≤ d ≤ 5 + 2f - e; e is an integer of 1 to 3; f is an integer of 0 to 2; wherein, R B as described above Y 3 is a single bond, phenylene or naphthylene, or a linking group having 1 to 12 carbon atoms with an ester bond, an ether bond or a lactone ring; R 24 is an acid-labile group; the chemically amplified positive resist composition further comprises a polymer containing fluorine atoms, and the polymer containing fluorine atoms contains at least one selected from the repeating units represented by the following formula (D3), the repeating units represented by the following formula (D4), the repeating units represented by the following formula (D5), and the repeating units represented by the following formula (D6), and may further contain at least one selected from the repeating units represented by the following formula (D1) and the repeating units represented by the following formula (D2); wherein, R C each independently represents a hydrogen atom or a methyl group, R D each independently is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group R 101 is a hydrogen atom, or a linear or branched hydrocarbon group having 1 to 5 carbon atoms in which a heteroatom-containing group may be inserted between carbon-carbon bonds. R 102 is a linear or branched hydrocarbon group having 1 to 5 carbon atoms in which a heteroatom-containing group may also be inserted between carbon-carbon bonds. R 103 is a saturated hydrocarbon group having 1 to 20 carbon atoms in which at least one hydrogen atom is replaced by a fluorine atom, and a part of -CH2- constituting the saturated hydrocarbon group may also be replaced by an ester bond or an ether bond. R 104 、R 105 、R 107 and R 108 each independently represents a hydrogen atom or a saturated hydrocarbon group having 1 to 10 carbon atoms, R 106 、R 109 、R 110 and R 111 are each independently a hydrogen atom, a hydrocarbon group having 1 to 15 carbon atoms, a fluorinated hydrocarbon group having 1 to 15 carbon atoms, or an acid-labile group. When R 106 、R 109 、R 110 and R 111 are a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group may be inserted between the carbon-carbon bonds; x is an integer of 1 to 3, y is an integer satisfying 0 ≤ y ≤ 5 + 2z - x, z is 0 or 1, m is an integer of 1 to 3, Z 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, where * is an atomic bond between the carbon atom of the main chain, Z 2 is a single bond, -O-, *-C(=O)-O-Z 21 -Z 22 - or *-C(=O)-NH-Z 21 -Z 22 -, Z 21 is a single bond or a saturated alkylene group with 1 to 10 carbon atoms, Z 22 is a single bond, an ester bond, an ether bond or a sulfonamide bond, * is an atomic bond between the carbon atom of the main chain Z 3 is a (m + 1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (m + 1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms.

2. The chemically amplified positive resist composition according to claim 1, wherein, the acid-generating unit is a repeating unit represented by the following formula (A4), the unit having a phenolic hydroxyl group is a repeating unit represented by the following formula (B1-1), the unit in which the phenolic hydroxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (B2-1), the unit in which the carboxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (B3-1); In the formula, R A , R B , X 4 , R 9 , R 10 , R 11 , b and k 1 are the same as described above. Y 3A is a single bond, a phenylene group or a naphthylene group, R 25 and R 26 each independently represents an acid-labile group having an aromatic hydrocarbon group with 6 to 20 carbon atoms and / or an alicyclic hydrocarbon group with 5 to 20 carbon atoms.

3. The chemically amplified positive resist composition according to claim 2, wherein, the base polymer comprises a polymer containing the repeating unit represented by formula (A4), the repeating unit represented by (B1-1), the repeating unit represented by (B2-1), and the repeating unit represented by (B3-1).

4. The chemically amplified positive resist composition according to any one of claims 1 to 3, wherein The polymer contained in the base polymer further contains a repeating unit represented by any one of the following formulas (C1) to (C3); In the formula, R B As described above, g and h are each independently an integer of 0 to 4, i is an integer of 0 to 5, j is an integer of 0 to 2, R 31 and R 32 each independently represents a hydroxyl group, a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 8 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbon oxy group having 1 to 8 carbon atoms which may be substituted by a halogen atom, R 33 is an acetyl group, a saturated hydrocarbon group having 1 to 20 carbon atoms, a saturated hydrocarbon oxy group having 1 to 20 carbon atoms, a saturated hydrocarbon carbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbon oxyhydrocarbon group having 2 to 20 carbon atoms, a saturated hydrocarbon sulfhydrocarbon group having 2 to 20 carbon atoms, a halogen atom, a nitro group or a cyano group, and may also be a hydroxyl group when j is 1 or 2. Y 4 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, where * is an atomic bond between the carbon atom of the main chain, A 3 is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a part of -CH2- constituting the saturated alkylene group may also be substituted by -O-.

5. The chemically amplified positive resist composition according to any one of claims 1 to 3, wherein, The base polymer further comprises a polymer containing repeating units represented by the following formula (B1) and at least one selected from repeating units represented by the following formula (B2) and repeating units represented by the following formula (B3), and not containing repeating units represented by formulas (A1) to (A8).

6. The chemically amplified positive resist composition according to any one of claims 1 to 3 further contains an organic solvent.

7. The chemically amplified positive resist composition according to any one of claims 1 to 3 further contains a photoacid generator.

8. The chemically amplified positive resist composition according to claim 7, wherein, The acid strength (pKa) of the anion of the photoacid generator is -2.0 or more.

9. The chemically amplified positive resist composition according to any one of claims 1 to 3, wherein The dissolution rate of the overexposed portion of the resist film obtained from the chemically amplified positive resist composition is 50 nm / sec or more.

10. A method for forming a resist pattern, comprising the following steps: forming a resist film on a substrate using the chemically amplified positive resist composition according to any one of claims 1 to 9, irradiating the resist film with a high-energy ray to form a pattern, and developing the resist film having the irradiated pattern with an alkali developer.

11. The method for forming a resist pattern according to claim 10, wherein, The high-energy ray is extreme ultraviolet light or an electron beam.

12. The method for forming a resist pattern according to claim 10 or 11, wherein, The outermost surface of the substrate is made of a material containing at least one selected from chromium, silicon, tantalum, molybdenum, cobalt, nickel, tungsten, and tin.

13. The method for forming a resist pattern according to claim 10 or 11, wherein, The substrate is a blank photomask.

14. A blank photomask coated with the chemically amplified positive resist composition according to any one of claims 1 to 9.

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